It was formerly the seat of the Bishop of Amelia, in existence from not later than the 5th century, but since 1983 has been a co-cathedral in the Diocese of Terni-Narni-Amelia.
Amelia Cathedral, dedicated to Saint Firmina, was built originally in 872.
That building was destroyed by the troops of Emperor Frederick II in the 13th century, and was rebuilt in Gothic style.
The present façade of pink cotto was completed only in the 19th century, after a destructive earthquake in 1822.
A number of notable works of art are housed here, including a depiction of the Last Supper (1538) painted by Giovanni Francesco Perini, the tomb of the Geraldini (1476) by Agostino di Duccio, a Madonna and Child attributed to Antoniazzo Romano, the Chapel of the Farattini containing among other items the funerary monument of Baldo Farrattini (bishop of Amelia 1558-62) by Ippolito Scalza,[1] and works by Niccolò Circignani, Federico or Taddeo Zuccari, and a modern copy of the stolen original of a "Martyrdom of Saint Firmina" by Lavinia Fontana.